perf: skip saving to emit cache after first failure (#24896)

2 files changed, 17 insertions, 9 deletions

diff --git a/cli/cache/emit.rs b/cli/cache/emit.rs
index 1d903fbba..fcec9e84b 100644
--- a/cli/cache/emit.rs
+++ b/cli/cache/emit.rs
@@ -6,6 +6,7 @@ use deno_ast::ModuleSpecifier;
 use deno_core::anyhow::anyhow;
 use deno_core::error::AnyError;
 use deno_core::serde_json;
+use deno_core::unsync::sync::AtomicFlag;
 use serde::Deserialize;
 use serde::Serialize;
 
@@ -19,10 +20,10 @@ struct EmitMetadata {
 }
 
 /// The cache that stores previously emitted files.
-#[derive(Clone)]
 pub struct EmitCache {
   disk_cache: DiskCache,
   cli_version: &'static str,
+  emit_failed_flag: AtomicFlag,
 }
 
 impl EmitCache {
@@ -30,6 +31,7 @@ impl EmitCache {
     Self {
       disk_cache,
       cli_version: crate::version::deno(),
+      emit_failed_flag: Default::default(),
     }
   }
 
@@ -87,12 +89,10 @@ impl EmitCache {
     code: &[u8],
   ) {
     if let Err(err) = self.set_emit_code_result(specifier, source_hash, code) {
-      // should never error here, but if it ever does don't fail
-      if cfg!(debug_assertions) {
-        panic!("Error saving emit data ({specifier}): {err}");
-      } else {
-        log::debug!("Error saving emit data({}): {}", specifier, err);
-      }
+      // might error in cases such as a readonly file system
+      log::debug!("Error saving emit data ({}): {}", specifier, err);
+      // assume the cache can't be written to and disable caching to it
+      self.emit_failed_flag.raise();
     }
   }
 
@@ -102,6 +102,11 @@ impl EmitCache {
     source_hash: u64,
     code: &[u8],
   ) -> Result<(), AnyError> {
+    if self.emit_failed_flag.is_raised() {
+      log::debug!("Skipped emit cache save of {}", specifier);
+      return Ok(());
+    }
+
     let meta_filename = self
       .get_meta_filename(specifier)
       .ok_or_else(|| anyhow!("Could not get meta filename."))?;
@@ -161,6 +166,7 @@ mod test {
     let cache = EmitCache {
       disk_cache: disk_cache.clone(),
       cli_version: "1.0.0",
+      emit_failed_flag: Default::default(),
     };
     let to_string =
       |bytes: Vec<u8>| -> String { String::from_utf8(bytes).unwrap() };
@@ -192,6 +198,7 @@ mod test {
     let cache = EmitCache {
       disk_cache: disk_cache.clone(),
       cli_version: "2.0.0",
+      emit_failed_flag: Default::default(),
     };
     assert_eq!(cache.get_emit_code(&specifier1, 10), None);
     cache.set_emit_code(&specifier1, 5, emit_code1.as_bytes());
@@ -200,6 +207,7 @@ mod test {
     let cache = EmitCache {
       disk_cache,
       cli_version: "2.0.0",
+      emit_failed_flag: Default::default(),
     };
     assert_eq!(
       cache.get_emit_code(&specifier1, 5).map(to_string),
diff --git a/cli/cache/mod.rs b/cli/cache/mod.rs
index 3430f74f7..772d2359d 100644
--- a/cli/cache/mod.rs
+++ b/cli/cache/mod.rs
@@ -106,7 +106,7 @@ pub use deno_cache_dir::HttpCache;
 /// A "wrapper" for the FileFetcher and DiskCache for the Deno CLI that provides
 /// a concise interface to the DENO_DIR when building module graphs.
 pub struct FetchCacher {
-  emit_cache: EmitCache,
+  emit_cache: Arc<EmitCache>,
   file_fetcher: Arc<FileFetcher>,
   file_header_overrides: HashMap<ModuleSpecifier, HashMap<String, String>>,
   global_http_cache: Arc<GlobalHttpCache>,
@@ -118,7 +118,7 @@ pub struct FetchCacher {
 
 impl FetchCacher {
   pub fn new(
-    emit_cache: EmitCache,
+    emit_cache: Arc<EmitCache>,
     file_fetcher: Arc<FileFetcher>,
     file_header_overrides: HashMap<ModuleSpecifier, HashMap<String, String>>,
     global_http_cache: Arc<GlobalHttpCache>,